1. Technical Field
The present invention relates generally to exercise equipment and, more particularly, to an exercise device permitting a user to perform walking, running, cross-country skiing and stair stepping exercises.
2. Background Information
A variety of exercise devices have been developed to simulate activities found to be effective in conditioning the body. One type of exercise device, exemplified by U.S. Pat. No. 3,970,302 to McFee, U.S. Pat. No. 4,685,666 to DeCloux, and U.S. Pat. No. 5,129,872 to Dalton et al. permits a user to perform a stair stepping exercise simulating climbing stairs. Another type of exercise device, exemplified by U.S. Pat. No. 4,850,585 to Dalebout, and U.S. Pat. No. 5,419,747 to Piaget, permits a user to perform a striding exercise simulating cross-country skiing or skating.
A disadvantage of such exercise devices is that the user cannot change the type of exercise being performed without mechanical adjustment of the device. One exercise device, exemplified by U.S. Pat. Nos. 5,290,211 and 5,401,226 to Stearns permits a user standing on foot supports to perform simultaneously a stair stepping or climbing type exercise and a cross country skiing or skating type exercise. The foot supports are mounted on a pair of generally horizontal linkages pivotally connected to a pair of vertical linkages at a first pivot location disposed at about the same elevation as the user's feet allowing the horizontal linkage to pivot up and down. The vertical linkages are pivotally connected to a frame at a second pivot location spaced forwardly of the user's feet and hips allowing the vertical linkages to move back and forth. While this type of device permits multiple exercises to be performed, it suffers from many disadvantages when used to simulate some of the exercises described above. For example, a disadvantage of mounting the horizontal linkages in cantilevered relation to the vertical linkages is that some force-resisting member is needed to prevent the foot supports from impacting the floor during use. In addition, complicated and costly mechanisms such as parallelogram linkages are needed to counteract tilting of the foot supports in directions apposed to the natural direction or tilt of the user's feet during certain types of exercises; and, even with such tilt correcting mechanisms, the foot supports are always maintained in a general position which does not necessarily correspond to the natural movement of the feet during certain exercises. Also, when used to perform exercises involving swinging of the vertical linkages relative to the frame, the placement of the upper pivots forward of the user's hip causes the foot supports to move in an arc having a geometric center offset from the user's hips, thereby detracting from the overall feel and stability of the device.